Method and apparatus for producing multiple sheet glazing units



Aug. 24, 1965 J. A. woons ETAL.

METHOD AND APPARATUS FOR PRODUCING MULTIPLE SHEET GLAZING UNITS 7Sheets-Sheet 1 Original Filed July 25, 1962 a 3nneutor$ WM a y We Aug.24, 1965 J. A. WOODS ETAL 3,202,494

METHOD AND APPARATUS FOR PRODUCING MULTIPLE SHEET GLAZING UNITS OriginalFiled July 25, 1962 7 Sheets-Sheet 2 I 1 14;.4 my 5 as i d FnventorfiAug. 24, 1965 J. WOODS ETAL METHOD AND APPARATUS FOR PRODUCING MULTIPLESHEET GLAZING UNITS '7 Sheets-Sheet 3 Original Filed July 25, 1962 Aug.24, 1965 J. A. woonns ETAL 3,202,494

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Aug. 24, 1965 J. A. WOODS ETAL METHOD AND APPARATUS FOR PRODUCINGMULTIPLE SHEET GLAZING UNITS Original Filed July 25, 1962 United StatesPatent Ofice EidZAdd iatented Aug. 2%, 1%55 El A 3,2il2, -'--4- MEIHUDAND FQR PRQBUEENL} UNETS John A. Woods, Lancaster, @hio, Donaid E.Sharp, de-

ceased, late oi v aumce, @hic, by @hio Citizens Trust Co., executor,Toledo, (Erie, and if-red E. Badger, lvlaumee, fihio, assiguors toLibbey-@wcns-Ford Glass Company, Toiedo, @hio, a. corporation of @hio(Tontinuation of application Ser. No. 567,135, Felt. 23, 1955, which isa continuation of application Ser. No. 309,834, Juiy25, 1352. Thisapplication Apr. 12, N69, Ser. No. 21,632

3 Claims. ((31. 6558) The present application is a continuation ofapplication Serial No. 567,185, filed February 23, 1956, now abandoned,which is a continuation of application Serial No. 300,884, filed July25, 1952, now abandoned.

This invention relates broadly to all-glass multiple sheet glazingunits. In particular, it relates to an apparatus and method for sealingtogether the marginal edge portions of spaced sheets of glass to producea hermetically sealed glazing unit, the sides of which are formed by theunion of said marginal edge portions.

Multiple sheet glazing units may be described generally as comprisingtwo or more sheets or" glass which are sealed entirely around theirmarginal edge portions in spaced relation to provide a hermeticallysealed dead air space therebetwecn. Due principally to their insulatingand condensation preventing qualities, such units have become wellestablished fixtures in the building trades and have found wide usage aswindows for buildings, show cases, vehicles, refrigerators, and thelike.

in the early development of the multiple sheet glazing art, it wascustomary to seal together the marginal edge portions of the spacedsheets of glass by means of strips of a substantially imperviousmaterial which were placed between said portions and bonded thereto inany suitable manner. In many cases, the seal so produced was found notto be hermetic and the unit thus impractical for the purposes ofimproved insulation and the prevention of condensation. As Well, inother instances, the sealing process was found to be so cumbersome andexpensive that production on a mass basis was practically impossible.

it has been found in accordance with this invention, that a hermeticallysealed glazing unit can be formed entirely of glass by means of a methodwhich is relatively simple, inexpensive, and well-suited to massproduction techniques.

It is therefore an object of this invention to provide a hermeticallysealed, all-glass multiple sheet glazing unit and in particular toprovide a relatively simple and inexpensive method of forming suchunits.

Another object of this invention is to provide a novel method forsealing together the marginal edge portions of spaced sheets of glass toform a hermetically sealed space therebetween.

Another object of this invention is to provide a method of producingmultiple sheet glazing units in which the marginal edge portions ofspaced sheets of glass are heated to the bending temperature thereof andfused in ealing relation with one another.

Still another object is to provide a novel apparatus for producingall-glass multiple sheet glazing units in accordance with the method ofthis invention.

Still another object is to provide an apparatus for producing multiplesheet glazing units comprising a furnace, a heat source in the furnace,means for supporting sheets of glass in fixed spaced face-to-facerelation, and means for moving said supporting means and heat sourcerelative to and past one another to progressively seal the edge portionsof the sheets together.

Briefly stated, this invention contemplates the production ofhermetically sealed glazing units made entirely of glass by means of amethod and apparatus in which two or more sheets of glass are supportedin fixed spaced facc-to-face relation and moved past concentrated heatsources to cause the marginal edge portions thereof to unite and therebyseal off a dead air space between said sheets. Thus, according to theinvention, concentrated heat sources may be directed to first one andthen the other pair of opposite marginal edge portions of the glasssheets, as they are supported in fixed spaced relation and movedtherepast, to cause said edge portions to become molten and unite withone anothen Or, it preferred, the marginal edges of the glass sheets canbe sequentially sealed by subecting first one edge and then another edgeto the action of the heating means.

In the accompanying drawings, wherein like numerals are employed todesignate like parts throughout the same:

FIG. 1 is a perspective view or" an all-glass multiple sheet glazingunit produced in accordance with this invention;

FIG. 2 is a perspective sectional View of one corner of the glazing unittaken substantially along line 22 of FIG. 1;

FIG. 3 is an over-all perspective view of an apparatus for producing theglazing unit and showing the furnace, conveyor, and burners;

FIG. 4- is a fragmentary sectional view of marginal edge portions of oneside of spaced sheets of glass prior to being subjected to aconcentrated heat source;

F365. 5 to 7 are fragmentary sectional views of said edge portions asthe heat source is applied thereto and they are caused to soften andbend into contacting relation With one another;

FIG. 8 is a fragmentary sectional view of said edge portions after theyhave been fused under the influence of said heat source to hermeticallyseal the side of the glazing unit;

FIG. 9 is a representation of a photograph of a cross section of atypical seal for a side of a glazing unit produced in accordance withthis invention and showing by illumination and magnification the flowlines of the fused portions of said side;

PEG. 10 is a fragmentary perspective view of a tray with the spacedglass sheets supported thereon;

FIG. 11 is an enlarged plan View of one of the supporting arms of thetray in supporting position;

FIG. 12 is a sectional view of the supporting arm taken substantiallyalong line lit-d2 of MG. 11;

FIG. 13 is a longitudinal sectional view of the furnace, takensubstantially along line 13-ll3 of FIG. 3, and showing the tray prior toits movement past one of the burners;

FIG. 14 is a transverse sectional view of the furnace, takensubstantially along line l4-14 of FIG. 13, with the tray removed;

FIG. 15 is a detailed perspective view of an adjusting device for aknock-out pin adapted to engage the tray supporting arms and move thesame to a non-supporting position;

FIG. 16 is an enlarged transverse sectional view of a portion of thefurnace and one of the burners, similar to FIG. 14 but showing the trayin operative relation with one of the burner heads;

FIG. 17 is an enlarged detailed sectional view of one of the pivotablehinge connections for the burner head of FIG. 16;

FIG. 18 is a plan view of one of the burners and a portion of thefurnace shown in FIG. 16;

A and B are burners 37.

sealed unit. 7

7 FIG. 19 is a transverse sectional view of the burner of i FIG. 18taken substantially along the line 19-ll9;

FIG. 20 is a plan view of a limiting device for the burner of FIG. 18,taken substantially along line 29- 2%) of FIG. 19;

FIG. 21 is a frontyiew of one of the burner heads;

FIG. 22 is a longitudinal sectional view of the burner head, takensubstantially along line 2222 of FIG. 21, and the gas inlet and coolantinlet and outlet thereto;

FIG. 23 is an enlarged transverse sectional view of the burner head,taken substantially along line 2323 of FIG. 22; I

' FIG. 24' is a transverse sectional view of the burner head, takensubstantially along line 24-24 of FIG. 22; 7 FIG. 25 is a transversesectional view of the burner head, taken substantially along line 25-25of FIG. 22;

FIG. 26 is a transverse sectional view of the burner FIG. 27 is asectional View, taken substantially along line 27--27 of FIG. 22 andshowing the gas'inlet and coolant inlet and outlet of the burner head.

Referring now to the drawings, there is shown in FIG. 3 a perspectiveview of an apparatus 30 by means of which an all-glass, multiple sheetglazing unit 31 may be produced in a manner to be hereinafter described.This apparatus includes a generally U shaped, horizontally movableconveyor 32, over which are mounted, in order of use, a preheatingcompartment 33 and a furnace 34, conforming in shape generally to saidconveyor. the furnace there are arranged, between the entrance 35 andexit 36 thereof, a first sealing area A, a second sealing :area B, andan annealing area C. Disposed outwardly of the furnace at opposite sidesof sealing areas The all-glass, multiple sheet glazing unit 31, producedin accordance with this invention, comprises upper and lower sheets ofglass 33 and 39, respectively, and side portions 40 between the marginaledge portions of said sheets, forming therebetween an enclosed space 41Disposed toward an ,edge or corner of onesheet of the unit is adehydration hole 4-2,. (FIG. 1) which may be hermetically sealed tosealoil the enclosed space 41. v

' More particularly, the side portions 4% of the unit are composed of aninnerwall 43 substantially perpendicular to'upper and lower sheets 38and 39 and an outer wall 44 angularly disposed thereto to form anenlarged base portion 45 adjacent the marginal edge portions of saidlower sheet. rectangular in cross section and the outer periphery of theunit substantially trapezoidal. The corners. of enclosed space 41 at theintersection of inner wall 43 and sheets 38 and 39 arerounded orfilleted, as best shown in FIG. 9. a

As previously mentioned and in a mannento be more fully describedhereinafter, the all-glass unit 31 is pro duced by assembling the upperand lower sheets38 and 39in fixed spaced relation, as shown in FIG. 4,properly preheating the sheets, and moving them-past concentrated heatsources from burners 37 to cause the marginal edge portions thereof toprogressively soften, as shown in FIG.

5,'unite, asshown in FIGS. 6 and 7, and ultimatelybecome. sealed to oneanother, as in FIG. 8. t

As assembled and prior to being sealed,.upper sheet 38 is relativelylarger than lowersheet 39 such that a peripheral portion of said uppersheet extends outwardly ,7 beyond the marginal edge of the lower sheet.It is also cumulation of the marginal edges of said upper sheet at ofeach'corner of the the enlarged base portions 45 'When thespacedsheets'are moved therepast, the concentrat ed heat sources aredirected toward the marginal edge portions of opposite sides of thespaced sheets in lower sheet '39 and those of the lower sheet to curlup- Thus, enclosed space 41 is substantially Within 30' wardly a slightamount (FIG. 5). Toward the completion of the passage of the sheets pastthe heat sources,

such that the edges thereof will unite with the edge per-- tions of thelower sheet adjacent said lower sheet (FIG. 6). Further heating willcause the united marginal edge portions to become more molten and theline of fusion between the same to increase, as shown in FIG. 7. At thecompletion of the passage of the sheets past the heat sources, themarginal edge portions of the opposite sides of the sheets will befirmly united and fused to one another at the broad base portion 45(FIG. 3) to form a seal therebetween.

This'seal has been foundto be exceptionally strong and permanent ratherthan a source of weakness in the unit. To illustrate the manner in whichthe marginal edge portions are finally united, a photograph was taken ofa magnified cross section of a typical seal produced in accordance withthis invention and which had been illuminated frointhe rear, andis'represented in the drawings by FIG. 9'. As can be seen therefrom, theflow of the layers of molten glass is such that there is a relativelywide line of contact 47 at the. unionof the marginal edges of upper andlower sheets 38 and 39, thus adding to the strength of the lower cornerof the unit. Further, it can be seen from FIG. 2 that, due partly to theremoval of the corner portions 46 of upper sheet 38, the corners of thesealed unit are rounded and do not present protuberances which mightlater require removal in the assembly of the unit in a suitable sash.

1 In being moved past concentrated heat source to effect the sealdescribed above, upper and lower sheets 38 and 39 are supported inproperly spaced relation on a tray 48, which is moved on conveyor 32forwardly through furnace 34 and past burners 37 in a manner to bedescribed hereinafter. .An elevational view of the entire tray 43 isshown in FIG. 13 and an enlarged but fragmentary view of the same can beseen in FIG. 16. However, particular reference is had to FlGS. 10 to 12for a description of the novel construction of the tray and itsrespective parts.

In plan, the tray 43 corresponds substantially to the outline of theglass sheets supported thereby.' For purposes of illustration, thesheets and tray are shown as beported on the upper edge of said rim.Additional support may be provided for the suspended central portion ofsaid lower sheet by a rib 53 (FlG. 16) extending between opposite sidesof upper rim 5t and having a rounded upper edge in horizontal alignmentwith the upper edges of said rim.

A p'a n fie of sheet rnetal or other suitable material is secured ateach of its edges to struts 51 and braces 52 intermediate upper andlower rims 5t and 49. in this manner, in the case of breakage of theglass sheets, the particlesthereof are prevented from falling into theconveyor mechanism or onto the bottom of the furnace. As well, pan 54servesto shield thebottom of lower sheet 39 from the heat of the furnaceto prevent bending or bowing'of the suspended central portions thereof.Prior to the plac- 7 ing oflowersheet 39 on the upper rim of the tray,the

'lfiissubstantiallytrapezoidalin a transverse cross section. Adjacentthe upper rim of the tray and secured betweenthe apices of adjacentstruts 51. are a plurality of bearings 55 having vertically boredjournal openings 56. Pivotally mounted within each of the openings arepins 57 having headed portions 58 upon which are carried upper sheetsupporting arms 59.

The arms 59 are slidably received in a channel through the upper side ofsaid headed portions 58 and each of said arms is attached thereto by abolt 6?) extending through a slot 61 in said arm and threadedly receivedin said headed portion. Thus, upon loosening bolt 6d, arm 59 may bemoved a limited distance in a defined path through the channel of headedportion 58. Of course, upon tightening its respective bolt, each of thearms 59 may be securely locked in place in the desired position.

Each of said arms is indented at its inner end to form a ledge 52 forsupporting the marginal edge portions of upper sheet 38 in proper spacedrelation to those of lower sheet 39. Handles 63 extend outwardly fromthe opposite ends of the headed portions of each of the pins 57. Thus,each of the arms may be selectively swung by handles 63 in the plane ofsheets 33 and 3d from an upper sheet supporting position, as shown bythe three leftmost arms in FIG. 10, to a non-supporting or knocked-outposition, as shown by the rightmost arm in said figure.

Preparatory to mounting upper sheet above lower sheet 39, each of thearms 59 is swung to the supporting position and, if necessary, isadjusted in a direction perpendicular to the edge of the upper sheet tobe supported thereon such that said sheet will be supported by each ofthe ledges 62 in at least substantially vertically aligned relation withrespect to the lower sheet. When both upper and lower sheets 38 and 39have been properly assembled on tray 43, in the manner described, thetray may be placed upon conveyor 32 so as to be moved through thepreheating compartment 33 and furnace 34 and past concentrated heatsources in th form of burner heads on burners 3'7, as indicated by thebroken lines of FIG. 12. To prevent bending or bowing of marginallysupported upper sheet 3% during its passage through the furnace, stripsof glass cloth (not shown) may be placed over the top thereof to shadeall but its marginal edge portions from the concentrated heat sources.

Preheating compartment 33 is supported above conveyor 32 in slightlyspaced relation thereto and is provided with suitable interior heatingelements (not shown) by means of which sheets 38 and 39 may bepreheated, prior to their entry into furnace 34, for a purpose wellknown in the art. Doors 64 are provided at one side of the compartmentfor placing the tray and sheets on the conveyor inside the chamber. Anexit (not shown) at the side of the compartment facing the entrance ofthe furnace permits the tray 48 resting on conveyor 32 to be movedforwardly from the compartment to said furnace entrance. Alternatively,of course, sheets 38 and 39 may be properly preheated within the forwardend of the furnace, in which case merely changes in temperature controlwithin the furnace would be required.

Conveyor 32 is composed of a series of spaced, horizontally disposedrollers 6% supported at each end on horizontally disposed channels 66(FIG. 16) secured to the upper ends of uprights 67 which are spaced atintervals parallel to and at each side of furnace 34. Channels 68 aresecured to and extend between said uprights for supporting the bottom ofsaid furnace at an elevation intermediate the rollers and floor level.Enlarged feet 69 may be provided for the lower ends of uprights 67 asshown in FIG. 13.

Rollers 65 are preferably hollow cylinders formed of any suitablematerial and spaced apart along the length of the furnace a distancesufficient to provide adequate support for the length of tray 4% (FIG.13). The ends of the rollers extend through openings 76 in each side ofthe furnace and are provided with outwardly projecting spindles 71 whichare journale-d in bearin s 2 mounted on channels 66. Secured to oneouter end of each of said spindles is a sprocket wheel F3 adapted toactively engage with the upper run of link chain 74. As best shown inFIG. 16, the upper run of the chain is supported on a longitudinallyextending channel member 75 and the lowor run thereof on a similarmember 76, both of which are secured to uprights 6! outwardly thereof. Aguard '77 is secured to members 75 and 7 6 and may be provided with anupper flange portion 73 for protecting sprocket wheels 73 as well aslink chain '74.

Thus, by any suitable power means (not shown) link chain may be movedforward in the direction of the movement of tray 43 through furnace 34to cause rollers 65 to rotate in a corresponding direction for so movingsaid tray. It is to be understood, of course, that a similar mechanismmay be provided for each straight section of the conveyor 32, in thefirst and second sealing areas A and B and annealing area C of thefurnace. By means of a directional transfer mechanism (not shown) and bycoordinating the operation of the driving mechanisms for each conveyorsection, a continuous movement may be provided through furnace 34% fromthe entrance 35 to the exit 36 thereof.

Furnace 34 i of a generally U shape conforming to conveyor 32, aspreviously mentioned, and is composed of top and bottom walls 7d and dd,respectively, and side walls 81 of any suitable refractory material.Bottom wall be is supported by the channels 63 at a level spaced fromand below the rollers 65 of conveyor 32, and top wall 79 is elevatedabove said rollers a distance sufficient to permit the free movement oftray 48 through the furnace as well as the movement of the forwardportions of burners 37 through openings 32 in the side walls 81. Shields83 (FIG. 18) may be provided at the outer side of side walls 31 of thefurnace for covering the open spaces in openings 82 around burners 37.Gpenings S4 in said shields permit the passage of rollers 65therethrough.

As well, Selas type heating elements 85 may be provided in each sidewall of the furnace above and below the path of tray 48 (FIGS. 13 and14) at a number of locations along the length of said furnace formaintaining the respective locations at the desired temperature. Fuelgas for the heating elements 35 may be provided from any suitable source(not shown) to a conduit as (FIG. 14) above the furnace and supplied tosaid heating elements at each side of the furnace by branch pipes 37.The temperature of each area of the furnace may be controlled by anysuitable means, such a valves 88 on the branch pipes and proper heatdistribution obtained by means of the areas of the furnace above andbelow rollers 65.

Each of the burners 37 includes a burner head 89 and means for mountingsame in proper elevation with respect to upper and lower sheets 33 and39 on tray 43 when moved therepast, a knock-out pin 98 for engaginghandles 63 of the upper sheet supporting arms 5? of the tray, in amanner and for a purpose to be described, rails $1 adjacent opening 82.and disposed perpendicular to and outwardly from the side walls 81 ofthe furnace over which the burner head mounting means may be movedinwardly and outwardly of opening 82 and into operative position withrespect to the marginal edges of the glass sheets, and aligning rollers92 for properly orienting the tray and burner head with respect to oneanother during movement of the tray therepast.

Rails 91, upon which the burner head mounting means is supported andadapted to be guidably moved, are secured by any suitable means, such asbolts 93, to horizontally extending channels 94 which, in turn, aresupported from upright angle irons d5 to form a substantiallyrectangular table constructed independently of the fur trace. The lowerends of the uprights 95 may be provided with feet $6 and cross member 97(FEG. 16) may be extended between the webs of channels 94 to addrigidity to the table structure. As well, cross members 93 and aeoaasa99 may be extended between the lower ends of the uprights.

The mounting means for each of burner heads 87 is provided with a baseplate 1% having notched portions 181 at each side thereof for slidableengagement with the upper inner edges of rails 91. A series of lowercross bars 1112 may be releasably held in engagement with the oppositelower edges of the rails by means of bolt 1113 (FIG. 19). Thus, thecross bars 162, in addition to maintaining the burner head and mountingmeans therefor on rails 5 1, permits the base plate 111% to be eitherlocked in place or to be moved in frictional engagement over rails 11into the desired position relative to the furnace.

It is, of course, necessary in practicing this inventionthat themarginal edge portions of the glass sheets 38 and 39m be sealed be movedpast the burner heads 89 at each side thereof in perfectly alignedrelation.- That is, both the upper and lower rows of-nozzles 1M and 165,respectively, on the burner heads must be in parallel relation to andequally spaced from said marginal edge portions at both sides of thefurnace at all time during the passage of the sheets therepast. For thispurpose, there is provided, in accordance with thisinvention, anarrangernent whereby the forwardly moving tray 48 will be caused tocoact with rollers 92 of the opposed burners 37 to automatically disposethe nozzle rows 164 and 19:5 in properlyaligned relation with respect tothe marginal edge portions of the glass sheets.

To be more specific, burner heads 89 on each of the opposedburners aremounted above base plates 1% in such a manner asto be normallyresiliently urged inwardly toward one another. in addition, the mountingmeans for the burner'heads are pivotally connected to said base platesso as to be movable outwardly with respect thereto. Thus, when baseplates 1% are locked in place on rails 91, burner heads $9 of opposedburners may be caused to move outwardly from one another, and relativeto said base plates, from their normal inwardly urged position.

Thus, in practicing this invention, burners 37 may be moved into aposition in which the rollers 92 suspended from housings 1% secured tothe burner heads 89, will be spaced apart transversely of the furnace adistance just less than the length of the sides of lower rim 49 of tray48. Inthis manner, when the tray is moved forwardly in at leastapproximatelyaligned relation with the space between opposed rollers,the opposed sides of said rim will coact with the rollers for theopposed burner heads 89, in moving therepast, to cause said burner headsto move outwardly an amount just sufiicient to permit the opposite sidesof the lower rim of tray 48 to pass through the rollers 92 frictionallyengaged thereby. To put it another way, the opposed burner heads will bespread out by tray 48 from their normal position to what may be calledan operative or sealing position 7 1 Of course, when'tray 48 is sodisposed between the rollers 92 and the marginal edge portions of theglass sheets are actually being fused the burner heads 89 aremaintained'in the'operative position by the inwardly urged mountingmeans therefor. That is, the arrangement of saidmounting means above thebase plate 1% serves, when saidbase plate is rigidly locked in place, tocontoward the forward (uppermost in FIG. 18) end of the furnace, isrelatively shorter than sleeve 108 and is'pivotally mounted at itsoutwardly disposed end above base plate 1% by a hinge connection 110.The longer sleeve 1118, on the other hand, is pivotally mounted abovesaid base plate by two similar connections 110, one of which islocatedat its outwardly disposed end and the other at a point inwardlyof the connection for sleeve 107.

One of the hinge connections 109 is shown in detail in FIG. 17 andcomprises arms 111 secured to the rear wall of housing 106 and havingthreaded vertical openings 112. Suitably bored openings in a connectingarm 113 are journaled on opposed hinge pins 114, received in 1 a hubportion extending upwardly therethrough, over which a'journal opening inone end of said arm is adapted to pivot. The opposite end of swingingarm 116 is suitably bored to receive the hub portion of a similar pin118 which extends downwardly through a bearing sleeve 119 received inopenings through either of the sleeves 107 As can'be seen from FIG. 18,the tubular columns 115 and axes of binge pins 117 for each of theconnections 111 are disposed in substantial alignment along thelongitudinal axis of base plate 190. Thus, in the operative or sealingposition of the burner (as shown in said figure), sleeves 107 and 1418are in substantially parallel relation. As well, it will be understoodthat in swinging on the two hinge connections 11%, sleeve 108 willtraverse paths which are at all times parallel to one another. On theother hand, it is equally 'apparentthatsleeve 107, swinging on only..the single hinge connection 110, will move in paths the directions ofwhich relative to one another will be dependent on the movement ofburner heads 89. Thus, there is provided, in a manner to be more fullyexplained hereinafter, an arrangement for mounting the burner headswhich will automatically give and subsequently right itself as theburner 37 is contacted by and aligned with a side of tray 48.

stantly maintain the rollers 92 for each of the burner heads infrictional engagement with the opposed sides of rim 49.. it will'beunderstood, therefore, that when said tray is disposed between all fourrollers, two on each side, the rows of nozzles on the burner headswillauto,-

matically be properly aligned with respectto the opposed marginal edgeportions of the glass sheets 33 and39.

Dealing now specifically with the arrangement of the mounting means foreach of said burner heads, mounting sleeves 1117 and 1118 are attachedat their inwardly disposed-ends to the rear wall of the housing- 1% bymeans of pivotal hinge connections 109. Sleeve 107, disposed As a meansfor normally urging the mounting means for opposite burner headsinwardly toward one another, tension springs 120 (shown in detail inFIG. 20) are extended between swinging arms 11s on the hinge connection11s for sleeve 107 and a portion of base plate as well as betweenswinging arm 116 on the rear connection 11%) for sleeve 168 and anotherportion of said base plate. In both instances, however, the portion ofbase plate 190, to which one end of spring 126 is attached, is forwardlyof the arm to which the other end of the spring is attached. Thus,tension springs 120 provide resilient means for normally urging each ofthe sleeves inwardly.

Dealing now specifically with one of said tension springs, bracket 121,securely mounted on base plate 16.0, includes at oneend thereof anupstanding arm 122 having an op ning through which apin 123;may bethreaded. The tension spring 120 is hooked at one end through an eye onsaid pin and at thc'other end to a small plate-124 secured to swingingarm 116. The tension in said spring may be adjusted by the manipulationof pin 123 and lock nuts 125. At the opposite end of bracket 121,upstanding arm 126 receives, through a threaded opening therein, a limitscrew 127 which is disposed in alignment with the side edge of'arm 116.By means 'of lock nut 128, the end of said screw may be adjustablypositioned, as desire-d, to limit the positiont-o which; swinging armmay be urged in i wardly by tension spring 120. r

i Asshown in FIGS. 18 and 20, for example, the burner head mountingmeans is in the operative position in which the swinging arms 11s foreach of the hinge connections 110 are disposed parallel to one anotherand perpendicu ar to the parallel sleeves 1&7 and 108. In this position,each of the arms 116 is urged outwardly against the tension in springs12% and is spaced slightly from the end of limit screws 127. On theother hand, in the normal inwardly disposed position of burner heads 89,the adjacent side edges of arms 116 will be in abutting relation withsaid limit screws such that each of the arms is disposed at leastgenerally obliquely to sleeves 167 and 1%. Thus, it will be understoodthat the front face of burner heads 89, and the rows of nozzles 16 i and1% will be moved from one position parallel to the movement of conveyor32 and tray 48 supported thereon to another position spaced from butparallel to said first-mentioned position.

Of course, in the normal position, none of the rollers 92 have beencontacted by lower rim 49 of tray 48. In the operative position,however, the tray is disposed between all four rollers. Intermediatethese positions, only the forward rollers, one on each opposite burner,is engaged by the forward end of the tray. Thus, as the forward end ofthe tray moves into the engaging position with the for- Ward rollers,the burner head mounting means Will be caused to undergo the giveaforementioned.

Specifically, on each burner head 89 the forward rollers will be movedoutwardly causing sleeve 197 to swing on its hinge connection 109. As aresult, arm 116 of sleeve 197 will swing in the opposite direction onhinge pin 117 away from its limit screw 12.7 and assume a position atleast approximately perpendicular to the longitudinal axis of base plate1%. As the tray 48 moves further past burner heads 89, its forward endwill engage the rear rollers 92 as the forward rollers are maintained intheir outwardly disposed position. In compensating for the movement ofthe rear rollers, each sleeve 168 will be swung on its hinge connection189 and arms 116 for each of said sleeves will be swung in the oppositedirection to assume positions at least approximately parallel to the 116for sleeve 137. Of course, as tray 48 travels still further, lower rim49 will move out of engaging position with forward rollers 92 and thearm 116 for each sleeve 107 will return to its position in abuttingrelation with limit screw 127. When the tray is moved its entire lengthpast the rollers, the arms 116 for each sleeve 1th; will assume similarpositions, at which time the burners will have returned to their normalinwardly disposed position.

As previously mentioned, it is necessary that the rows of nozzles liloand 195 on opposed burner heads 89 be disposed in perfectly alignedrelation to the opposite edge portions of the sheets 38 and 39 duringthe actual sealing of said edges. That is, it is an important feature ofthis invention that the flames from the nozzles be directed t the edgesof the sheets in a predetermined and constantly maintained relationduring the actual sealing thereof.

Therefore, to provide the proper coordination between the aligning ofthe opposite edges of the glass sheets with the burner heads '39 and theactual sealing of said edges, the tray 48 is specially constructed, in amanner previously described. That is, the cross section of the tray asis substantially trapezoidal with lower rim 49 thereof pro- ,iecting .asubstantial distance outwardly beyond upper rim As will be more fullyunderstood from FIG. 13, the amount of this projection is slightlygreater than the longitudinal distance between rollers 92 on each burnerhead. In this manner, prior to the passage of any portion of theopposite side edges of the sheets 33 and 39 past the nozzles of theburner heads 89, those portions of lower rim 49 projecting beyond upperrim 50 will have moved said burner heads to the operative or sealingposition. 'In like manner, the burner heads 59 will be maintained in theoperative position by the similar projecting portions of lower rim 49 atthe rear end of the tray until the entire lengths of the opposite edgeshave been sealed.

The actual sealing of the marginal edge portions of upper and lowersheets 38 and 39 is performed progressively along opposed sides of saidsheets. That is, as they are passed by the burner heads 89, the marginaledge po tions of the sheets are almost instantaneously fused toe getheras the flames from the rows of nozzles 104 and 195 are playedtherealong. That is, each portion of said opposed edges is moved pastthe entire length of the upper and lower rows of burner head nozzlesand, after having so passed, each of said portions is almostinstantaneously fused as its spaced marginal edge portions are renderedmolten and caused to unite in a manner previously described.

Upper sheet supporting arms 59 have also been previously described asbeing movable from a supporting to a non-supporting or knocked-outposition. For the purpose of progressively engaging the handles 63 ofthe arms on opposed sides of the tray 4S, as it is moved therepast,knock'out pins 96 are so supported from each of the opposite burners atthe forward sides thereof as to engage said handles just prior to themovement of those portions of the glass sheet marginal edge portionssupported thereby past the burner heads 559. That is, with particularreference to FIG. 13, it can be seen that as tray 48 moves pastknock-out" pins prior to moving past the burner head nozzles, each ofthe upper sheet supporting arm handles 63 will be progressively moved tothe knocked-out position.

In this manner, the opposed marginal edge portions of the sheets beingfused will at all times during the fusing thereof be supported inproperly spaced relation. That is, for example, as the supporting arms59 for the forward end of the upper sheet are removed from theirsupporting position and said forward end of the upper sheet is in theprocess of being fused with that of the lower, the remaining lengths ofthe opposed edges are maintained in properly spaced relation by theremaining arms 5d. As well, due to the fact that the fusion takes placealmost instantaneously, those portions of the opposite marginal edges,which have passed burner heads 39 and have been transformed into sideportions 40, also provide supports for properly spacing the sheet. Thus,by a combination of said fused portions of the sheets as well assupporting arms 59, upper and lower sheets 38 and 39 are at all timesduring the sealing operation maintained in properly spaced relation.

Knock-out pin t depends from a rod 129 which extends substantiallyparallel to sleeve N7 and is slidably received in a bearing sleeve 130(FIG. 15). Set screws 131 are received through the top of the sleeve forlocking rod 129 in place when it has been moved to the desired positionlongitudinally of the burner head mounting means. Threaded pins 132depend from sleeve 13%) and are received in slots 133 in the upper plate13 of an 1 shaped support member 135. Lock nuts 136 serve to support thesleeve on said pins 132, in fixed relation above upper plate 134. Thelock nuts may be loosened to permit pins 132 to be moved in slots 133vertically as well as transversely of the burner head mounting means.The lower plate of support member 135 may be secured to rail '91 inanysuitable manner.

By means then of the particular apparatus described in connection withFIG. 15, the knock-out pin 9i may be moved into any desired-position toengage handles 63 of the upper sheet supporting arms 59 at a point alongthe path of said tray which Will permit ledges 62 of said arms to beentirely removed from between glass sheets 38 and 39 prior to themovement of those portions of upper sheet 38 supported by said ledgespast the burner heads 89. Thus, as shown in FIG. 13, the pin 93 isspaced slightly forward of burner head 89 such that just after a ledge62 is entirely removed from a portion of the marginal edges of the glasssheets, flames from the rows of nozzles 104 and N5 will be directedthereto.

Although best results have been obtained by the particular arrangementof the burner head nozzles with relation to the marginal edge portionsof the glass sheets disclosed and described herein, it is to beunderstood that this invention is not restricted thereto. Generally,however, it-may be said that the nozzles on the burner heads should bearranged close enough to said marginal edge portions that the flamestherefrom will be actually played along said portions of both sheets,such that they will be caused to become molten and bend or curl insubstantially. thernanner previously described.

It has been found that in actual practice, with glass sheets ofapproximately /s"'thicknessand-spaced apart approximately A", apermanent seal may be obtained by arranging the burner head nozzles withrelation to said sheets in the manner shown in FIG. 12. As showntherein, the nozzles of the upper row 104 are spaced about As" aboveupper sheet 38 and are directed perpendicularly thereto in substantialalignment with the edge of lower sheet 39. The nozzles of the lower row1% are spaced a similar distance above the edge of lower'sheet 39 andare disposed at an angle of about 45 degrees to the plane thereof. 7

Thus, as the sheets are moved past the burner heads, the flames from theupper row 164 of nozzles will cause the marginal edge portions of theupper sheet to become molten and bend toward those of the lower sheet.Simultaneously, the flames from the lower row 1W5 of nozzles will causea relatively smaller part of the marginal edge portions of the lowersheet 39 to curl upwardly. When said marginal edge portions have unitedand reached approximately the position shown in F16. 6, theflames fromthe upper row of nozzles will further cause the united portions tobecome more molten and the line of fusion '47 to increase, as previouslydescribed with respect to FIG. 7. At the very final stages of thefusing, the flames from the lower row of nozzles will be played alongsaid line of fusion to perfect the seal between the side of the sheets.

The sealed molten marginal edge portions of the' Of course, a device ofthis kind may take any number of forms in which, for example, theforward end of the tray 48 is caused to actuate automatic means fortransferring said trayfrom one section of conveyor 32 to another. At anyrate, the particular mechanism for so indexing tray 48 does not formapart of this invention and is not illustrated herein. For that matter,rather than being constructed in the substantial U. shape shown, ifspace permits, furnace. 34- and conveyor 32 maybe constructed in eitheran L shape or a straight line.

Regardless of the particular shape of the furnace and conveyor, however,tray 48 is moved continuously through the furnace in a manner to exposefirstone and then the other pair of opposite edge portions of glasssheets 38 and'39 to the flames from the opposed burners 37. 'Althoughthe tray 48 has been shown herein as substantially I square, it will beunderstood that the positionof the sheets may be set and the suspendedinner portions prevented from sagging by a jet of air directed along thelengths thereof to rapidly cool the same shortly after theyhave passedthe burner head 89. Air for this purpose may be supplied from anysuitable source (not shown) and carried through a pipe 137 (FIG. 18)extending along the rear side of the burner head mounting means to anozzle 133 having a vertically directed opening disposed above the pathof the marginal edge portions of the glass sheets. The pi e 137 maybesupported along its length from a bracket 139 upstanding from rail 91and a mounting sleeve 14% secured to and spaced from therear side ofburner head 89.

Additional aligning rollers 141 are suspended from supports-142 securedto the side walls 81 of the furnace at each side thereof forwardly ofeachof the sealing areas A and B and in substantial alginment with thespace between the normally urged rollers 92 on burners 37. The rollers142 may be spaced apart a distance slightly greater than the Width ofthe lower rim of tray 48 for properly aligning the sameprior to itsmovement into engaging relation with rollers 92. If desired, the rollers141 may be suspended-from supports 142 in inwardly converging relation.

It'will also be understood that in sealing glass sheets 38 and 39entirely around the marginal edges thereof,

7 rear wall of housing 106.

burners may be adjusted to accommodate trays of most any rectangularshape.

Intense localized heating for sealing the marginal edge portions of theglass sheets is supplied by flames from an oxygen and natural gasmixture. For this purpose, the oxygen and gas for each 0f the burnerheads 89 are supplied from a suitable source (not shown) through pipes143 and 144, respectively, to a mixing chamber 145. From the mixingchamber 145, aconduit 146 extends 7 toward. burner head 89 and carriestheoxygen-fuel mixture to a flexible hose 147 which in turn is connectedto one end of an oxygen-fuel inlet pipe 148.- The inlet pipe 148 extendsthrough the entire length of aconcentrically arranged conduit 150 and isthreadedly received at its other end in the rear wall of the burnerhead. as shown in FIG. ,22. Both the inlet pipe and surrounding conduit150 are extended through an opening 149 in the rear wall of housing 166.Also, inlet pipe 148 may be supported toward its rear end on a block 151which in turn may be supported by struts 152. extending longitudinallyfrom the A coolant may be supplied from a suitable source (not shown)through a pipe 153 extending longitudinally of conduit 150 andthreadedly received in the rear wall of the burner head 89 at a point toone side of the threadedly received end of oxygen-fuel inlet'pipe 148.The coolant may be discharged from the burner'head, after circulatingthrough the cast manifold thereof, in a manner tobe 7 describedhereinafter, through a passage 154 in conduit conduit 150 and is secured'at its forward end in a mounting bracket 158cm the top wall of housing106. As 9 shown in FIG. 21, a reduced portion atthe forward end of therod 157 is received between upper and lower'clamping members 159 and160, releasably held in interfitting relation by pins 161. The adjustingrod 157 is provided with a threaded portion at its rear end which isreceived in a'bracket 162 mounted above conduit 150.

. 'Flange1163 (FIG. 22) on the side walls of housing'106 at the frontface thereof are provided with bearing sleeves 164 in their outer'legs.Rods 165 extend rearwardly from wing portions 166 at each side of theburner head 89 and are slidably received in the bearing sleeves 164 ofthe housing 106. Thus, a rotative movement of adjusting rod 157 willresult in the movement of the burner head inwardly or sired.

Turning now to theconstructionof each of the burner outwardly of itsmounting means, as de-' 13 heads 89, and with reference to FIGS. 21 to27, lower walls 167 and 168 thereof are disposed angularly to oneanother to direct flames from the upper and lower rows of nozzles 104and 105, respectively, in proper impinging relation to the marginal edgeportions of glass sheets 38 and 39. A series of passages are providedinteriorly of the burner head for the proper distribution of theoxygenfuel mixture from inlet pipe 148 to the individual nozzles 169.Another series of passages are provided for distributing the coolantfrom pipe 153 through the burner head, in substantially surroundingrelation to the oxygenfuel passages, to passage 154.

Passage 170 extends horizontally and transversly of the burner head 89as a continuation of the threaded socket for oxygen-fuel inlet pipe 148to a point just short of the front wall of said burner head. A passage171 is bored vertically from the upper wall of the burner head tointersect said threaded socket and extend downwardly therefrom to ahorizontally and longitudinally extending distributor passage 172 forthe lower row of nozzles Hi5. Threaded outlet passages 173 projectdownwardly from distributor passage 172 and perpendicular to the lowerWall 168 of the burner head at equally spaced locations along the lengththereof to provide sockets for threaded shanks on each of the nozzlesD39 of the lower row 165.

Passage 174 is bored upwardly from and perpendicular to the lower wall167 of the burner. head 89 to intersect with the end of horizontallyextending passage 17%. Distributor passage 175 for the upper row ofnozzles extends horizontally of the burner head and parallel todistributor passage 172 to cross the passage 174 at a point belowpassage 170. Outlet passages 176 (FIG. 22) project downwardly from thedistributor passage 175 in parallel relation to passage 174 at equallyspaced locations along said distributor passage and are threaded attheir lower ends similarly to the lower end of the passage 174, toreceive the shanks .of the nozzles 159 of the upper rows 164.

As best shown in FIG. 21, the nozzles 1139 of the upper row 184 arespaced apart from one another a distance equal to that of the spacingbetween the nozzles of the lower row 195. As well, the nozzles of theupper row are staggered with relation to those of the lower in such amanner that the impinging frames from said upper and lower rows ofnozzles will provide a substantially continuous, longitudinallyextending flame to the marginal edge portions of the glass sheets 38 and39 moving therepast.

Dealing now with the circulation of the coolant through burner head 89,:it can be seen that a short passage 177 extends inwardly as .acontinuation of the threaded socket for coolant inlet pipe 153 in therear wall of said burner head. Another short'passage 173 (FIG. 24) isbored vertically from the upper wall of the burner head to intersect atits lower end with the end of horizontal passage 177, and is intersectedat its upper end by a horizontally extending distributor passage 179which is bored from the rear wall of the burner head to a point justshort of the front wall thereof.

A series of passages, consisting of a relatively large passage 1'89 andsmaller passages 181 and 182 extend horizontally and longitudinally fromdistributor passage 179 in a direction away from the oxygen-fuel passage170. Each of said passages maybe bored parallel to one another and inproperly spaced relation from a side wall (rightmost in PKG. 22) of theburner head. At points just short of said side wall, another series ofpassages 183, 184 and 185 (FIG. 22) may be bored vertically through theupper wall of the burner head to intersect .horizontal passages 180, 181and 132, respectively.

Passage 183, corresponding in diameter to passage 180, extendsdownwardly therefrom to a point just short of lower wall 168 of theburner head where it connects with a relatively smaller passage 13:;extending horizonoases lid tally and longitudinally the entire length ofthe burner head. At its connection with the smaller passage 1%, verticalpassage 183 also leads to a similar passage 187 through a short passage138 (FIG. 24) which may be bored from the rear wall of the burner headparallel to lower face 163 thereof. Thus, passages 136 and 1 87,disposed on opposite sides of the lower row of nozzles, may be boredthrough the entire lengths of the burner head.

The opposite (leftmost in FIG. 22) ends of passages i185 and 187 areconnected by a short passage 139 (P16. '25) corre'sp-ondingt-o passage183 at the opposite end of the burner head, which leads to a verticallybored passage 190, corresponding to passage 1%. Toward the upper end ofpassage 1% adjacent the upper wall of the burner head, a passage 19extends inwardly and horizontally therefrom, in substantial alignmentwith passage 1%, and intersects at its opposite end with a collectingpassage 192. (FIG. 26), which extends transversely of the burner headsubstantially parallel to passage 17% at the side thereof opposite fromthe passage 177.

Vertically bored passages 184 and 185 extend to points just short of thelower wall 167 of the burner head 89 and intersect, respectively, withone end of horizontally and longitudinally extending passages 193 and194- disposed at opposite sides of the upper row of nozzles llld.Similarly to passages 1% and 137, at opposite sides of the lower row ofnozzles, passages 193 and 194 may be bored through the entire length ofthe burner head. Just short of the opposite side wall (leftmost in FIG.22) of the burner head, the opposite ends of passages 193 and ti -'9intersect, respectively, with vertically bored passages 195 and 1%,corresponding to vertical passages 184 and 135. The passages 195' and 1%are intersected by one end of horizontally and inwardly extendingpassages 197 and 198 (FIG. 25), respectively, which are in substantialalignment with passages 131 and 182 extending from distributor passagei179. The opposite ends of passages 197 and 198 connect with collectingpassage at points outwardly (rightmost in FiG. 26) of passage 191.

The collecting passage le -'2 may be bored from the rear wall of theburner head to a point adjacent the front Wall threof to accommodateintersecting passages 191, 19 7 and 198. A passage 1% may be boredvertically from the top wall of the burner head to intersect with andextend below collecting passage 3192, as shown in FIG. =26, a distancesufiicient to permit horizontally disposed coolant outlet passages Ztltito connect the lower end thereof to a portion of passage 154 in conduit15% adjacent recess in the rear wall of the burner head into which saidconduit is fitted.

Thus, each burner head 89 comprises a cast manifold having a firstseries of passages from which an oxygenfuel mixture may be distributedto two rows of nozzles on the lower walls thereof and a second ofpassages through which a coolant may be continuously circulated insubstantially surrounding relation to said first series of passages. Forexample, coolant passages 193 and 19 are disposed along opposite sidesof the entire length of oxygen-fuel distributor passage as well as thepassages 171 to the upper row m4 of nozzles. Similarly, coolant passages186 and 187 are disposed along opposite sides of the oxygen-fueldistributor passage 172 and the passages 16% to the lower row ofnozzles.

As previously described, each of the passages may be bored from thewalls of the burner head permitting said head to be integrally cast. Theouter openings of said passages may be plugged in any suitable manner,and all but the rear walls of the burner head may be covered with a thinmetallic coating 2%..

As mentioned previously, a dehydration hole 42 is disposed toward onecorner of one of the glass sheets. This hole serves, during the passageof the marginally sealed glazing unit 31 from the second sealing area Band through the annealing area C, as a breather per- V 169hare playedtherealong in 'the manner described,

varying temperatures. in the furnace 34. Upon removal. .of themarginally sealed unit from the furnace, the

space 41 may be dehydrated and the hole 42 hermetically sealed to ,sealofisaid space in its dehydrated condition. Anumber of different wellknown processes may be used in this final step of dehydrating andhermetically. sealing the space between the glass sheets 38 and 39, andthe size and shape ofthe hole 42 will generally depend on the particularprocess selected. However, since none of these processes forms a part ofthis invention; any suitable means may be employed.

Reviewing now the entire process which spaced sheets of glass maybesealed'around their marginal edges to produce anhermetically sealedglazing unit 31, initially the marginal edge portions of a sheet ofglass 3? areplaced on the upper edges of the upper rim 59 of tray 48.Arms 59 of the trayare then swung into supporting position such that themarginal edge portions of another sheet 38 may be supported on theledges 62. of said armsin properly spaced and vertically alignedrelation above the sheet 39..

The upper surface of the upper sheet 38 may besha'ded with glass clothor the like and the tray'4$; with both sheets supported thereon, placedin the preheating compartment .33 insuch a manner as .to be insubstantial alignment with opening 35 in'the furnace 34 andthespacebetween rollers 141 as well as the space between a the first set ofopposed burners 37 at sealing area A. The temperature of thecompartmentfifs is maintained at about 5 75 degrees Fahrenheit toproperly preheat the glass sheets 38 and 39 prior to theirentry into thefurnace. Of course, as mentioned previously, the preheating of the glasssheets may be performed in the forward end of the furnace, eliminatingthe need for a separate compartment.

' In any case, however, as the tray dfi is moved forwardly on conveyor32 and 'past aligning rollers 141;

the glass sheets 38 and 35 are progressively raised to a temperatureslightly short of the annealing temperature which, in most cases, isabout 1000 degrees Fahrenheit.

That is, the sheets are'heated to a level just short of their 7 strainpoint in moving into the first sealing area A.

As the tray moves into engaging relation with the opposed burners 137 ofthe first sealing area A,'which of'this' invention by at 90 degrees toits path through the first seaiingarea A. 1 In this manner; the unfusedpair of oppositemarginal edge portions willbe aligned with the directionof movement of the tray and the fused portions will be perpendicularthereto; Thus, with opposed burners 37 of the second sealing area B inproperly adjusted position j of sealing area B, glass sheets 38 and 39will be sealed entirely "around their marginal edge portions to, formenclosed space 41. As the marginally sealed sheets move into the secondcorner of furnace 34-between sealing area B and annealing area C, adirectional transferring device, similar to the onedisposed in the firstcorner of the furnace, will cause the movement of tray 48 to be changedanother 90 degrees. 3 a

In its oriented positiointray dfiwill be moved on the third section ofconveyor 32 through the annealingarea C- In'the' annealing area,thete'inperature of the furnace 'is; accurately controlled in'sucha'rnanner that it will be caused to drop gradually from "about 960degrees Fahrenheit at the end of said area adjacentsealing area B toabout 295 degrees adjacent theexitfid of the furnace glass sheets for a--purpose well known in the'art. V, f I V Of course, as the marginallysealed unit Slis removed from the conveyor 32 at the end of the furnace,it may be moved to any suitable'location for dehydrating the spaceil'therebetween and hermetically sealing hole 42, p as previouslymentioned.

It is to be understood that the forms of the invention disclosed hereinare to be takenzas. the preferre'd embodiments thereof, and that variouschanges in the shape,

- size and arrangement of parts'may'be resorted to withhave beenproperly adjusted in themanner described,

the opposite sides of the lower rim 4%! of the tray will engage" rearrollers 92 on the opposed burners to spread said burners from thenormalto theoperative position. As tray- 48 moves forwardly out ofengaging relation with the first set of burners, said burners willreturn or right themselves to the normal'position. During the movementof the tray past the first set of burners when they are disposed in theoperative posi tion, the marginal edge portions of the pair of oppositesides of the glass sheets adjacent said burners will be "progressivelyfused, as the arms 59 'sup'porting said op:

posite marginal edge portions of the upper sheet 38 are knocked out andflames from burner head nozzles As the tray 48 moves from the'firstsealing area A to I the directional transferring mechanism at thefcornerbetween said first sealing area and the secondsealing area B, uppersheet 38 will be properly supported above lower sheet 39 onone pair ofopposite sides by the marginal edge portions of both sheets which havebeen almost instantaneously fused atthe first sealing area to formsecond sealing area B, it too will be traveling in a path I anotherglass sheet, moving said marginal edge portions out departing from thespirit of the invention.

We claim: 7 M. l. A method of producing multiple sheet glazing units,which comprises supporting the marginal edge portions of one sheet ofglass in spaced relation above those of of the sbejets'as aunitrpast aheat source whichheats said marginal edge portions and causes them to befused to one'another, and progressively removingj'a' portion of thesupport for the upper sheet nearest the heat source prior to movement ofthe previously supported marginal edge portions of said sheets past saidheat source while retaining snpport for the sheet along areas fartherre-. moved from said heat source until the marginal edge portions aresealed substantially along their entire length.

' 2. A method of producing multiplesheet glazing units, which comprisessupporting a'marginal edge portion of an upper sheet of glass in spacedand outwardly project? ing relation above that of a lower sheet,directing a flame from a concentrated heat source downwardlyonto themarginal edge portion of the upper sheet in a direction substantiallyperpendicular to the plane of said sheet and in substantial alignmentwith the edge of said'lower sheet, and simultaneously directing anadditional flame downwardlyonto the. marginal edge portions ofsaid'lower sheet at an angle to the plane of said lower sheet.

3. A method of producing multiple sheet glazing units which comprises,supporting the marginal edge portions of one sheet of glass in spacedrelation above the corresponding portions of another glass sheet,movingthe marginal edge portions of both of'fsaid sheets at'oppositesides thereof past a'group of concentrated'heat sources to cause saidedge portions to be sealed together, removing the supports for saidmarginal edge portions of the upper sheet just prior to their movementpast said group of heat sources, orienting said sheets to sequentiallydispose the other marginal edge portions of both sheets at the otheropposite sides thereof in alignment with other groups of concentratedheat sources, sequentially moving said other marginal edge portions ofboth sheets past said other groups of concentrated heat sources to causesaid other edge portions to be sealed together, and sequentiallyremoving the supports for said other marginal edge portions of the uppersheet just prior to their movernen past said other groups ofconcentrated heat sources.

Reterences Cited by the Examiner UNITED STATES PATENTS 1,448,351 3/23Kirlin 65-34 2,194,755 3/40 Kell 65-47 2,389,360 11/45 Guyer et a1.65-40 2,24,979 1/ 53 Clever 6523 2,671,987 3/54 Iendrisak 65-1582,761,249 9/56 Olson et a] 65152 1 DONALL H. SYLVESTER, PrimaryExaminer.

CHARLES A. HODGES, ARTHUR P. KENT, MOR- RES 0. WOLK, Examliners.

ONITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No 3202,494 August 24, 1965 John A. Woods et a1.

It is hereby certified that error appears in the above numbered patentrequiring correction and that the said Letters Patent should read ascorrected below.

In the heading to the drawings, Sheets 1 to 7, line 3, for "July 25,1962", each occurrence, read July 25, 1952 column 14, line 55, after"second" insert series Signed and sealed this 5th day of April. 1966.

( L) Attest:

ERNEST W. SWIDER Attesting Officer BRENNER Commissioner of Patents

1. A METHOD OF PRODUCING MULTIPLE SHEET GLAZING UNITS, WHICH COMPRISESSUPPORTING THE MARGINAL EDGE PORTIONS OF ONE SHEET OF GLASS IN SPACERELATION ABOVE THOSE OF ANOTHER GLASS SHEET, MOVING SAID MARGINAL EDGEPORTIONS OF THE SHEETS AS A UNIT PAST A HEAT SOURCE WHICH HEATS SAIDMARGINAL EDGE PORTIONS AND CAUSES THEM TO BE FUSED TO ONE ANOTHER, ANDPROGRESSIVELY REMOVING A PORTION OF THE SUPPORT FOR THE UPPER SHEETNEAREST THE HEAT SOURCE PRIOR TO MOVEMENT OF THE PREVIOUSLY SUPPORTEDMARGINAL EDGE PROTIONS OF SAID SHEETS PAST SAID HEAT SOURCE WHILERETAINING SUPPORT FOR THE SHEET ALONG AREAS FARTHER REMOVED FROM SAIDHEAT SOURCE UNTIL THE MARGINAL EDGE PORTIONS ARE SEALED SUBSTANTIALLYALONG THEIR ENTIRE LENGTH.